648741221 has 4 divisors (see below), whose sum is σ = 648850944. Its totient is φ = 648631500.

The previous prime is 648741211. The next prime is 648741227. The reversal of 648741221 is 122147846.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-648741221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (648741227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45455 + ... + 57996.

It is an arithmetic number, because the mean of its divisors is an integer number (162212736).

Almost surely, 2^648741221 is an apocalyptic number.

It is an amenable number.

648741221 is a deficient number, since it is larger than the sum of its proper divisors (109723).

648741221 is a wasteful number, since it uses less digits than its factorization.

648741221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109722.

The product of its digits is 21504, while the sum is 35.

The square root of 648741221 is about 25470.3989171744. The cubic root of 648741221 is about 865.6795626544.

The spelling of 648741221 in words is "six hundred forty-eight million, seven hundred forty-one thousand, two hundred twenty-one".